Aspects of this disclosure relate generally to telecommunications, and more particularly to cell reselection for small cells and the like.
Wireless communication systems are widely deployed to provide various types of communication content, such as voice, data, and so on. Typical wireless communication systems are multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and others. These systems are often deployed in conformity with specifications such as Third Generation Partnership Project (3GPP), 3GPP Long Term Evolution (LTE), Ultra Mobile Broadband (UMB), Evolution Data Optimized (EV-DO), Institute of Electrical and Electronics Engineers (IEEE), etc.
In cellular networks, macro scale base stations (or macro NodeBs (MNBs)) provide connectivity and coverage to a large number of users over a certain geographical area. A macro network deployment is carefully planned, designed, and implemented to offer good coverage over the geographical region. Even such careful planning, however, cannot fully accommodate channel characteristics such as fading, multipath, shadowing, etc., especially in indoor environments. Indoor users therefore often face coverage issues (e.g., call outages and quality degradation) resulting in poor user experience.
To extend cellular coverage indoors, such as for residential homes and office buildings, additional small coverage, typically low power base stations have recently begun to be deployed to supplement conventional macro networks, providing more robust wireless coverage for mobile devices. These small coverage base stations are commonly referred to as Home NodeBs or Home eNBs (collectively, H(e)NBs), femto nodes, femto cells, small cells, small cell base stations, pico nodes, micro nodes, etc., deployed for incremental capacity growth, richer user experience, in-building or other specific geographic coverage, and so on. Such small coverage base stations may be connected to the Internet and the mobile operator's network via a digital subscriber line (DSL) router or a cable modem, for example.
Cell reselection from macro cells to small cells is generally supported on conventional cellular modems. However, current cellular communication standards such as those provided by 3GPP do not specify how to select a particular small cell candidate from: (1) multiple frequencies within a serving Radio Access Technology (RAT) of the macro cell; (2) multiple frequencies within a non-serving RAT; or (3) multiple frequencies from different RATs (e.g., one or more from a serving RAT or one or more from each non-serving RAT).
There accordingly remains a need for more robust reselection criteria and associated algorithms and systems, covering inter-RAT and intra-RAT small cell reselection.